1. Field of the Invention
The present invention relates to a plaster preparation, and, more particularly, to an analgesic, anti-inflammatory plaster preparation comprising pranoprofen.
2. Description of the Background
Pranoprofen is popularly used in clinics in forms such as tablets, capsules, and the like as a non-steroidal antiinflammatory and analgesic drug due to its excellent antiinflammatory and analgesic activity.
Non-steroidal anti-inflammatory and analgesic drugs usually exhibit a strong action to digestive organs after oral administration and, if dosed in a large amount, may cause side effects such as peptic ulcer and the like. Since pranoprofen exhibits such side effects only in a very limited degree, it is frequently used in clinics. However, pranoprofen is not always without risks of side effects; it is sometimes accompanied by side effects in digestive organs, such as peptic ulcer, bleeding in gastrointestinal tracts, constipation, diarrhea, and the like.
A cutaneous application of pranoprofen can reduce the side effects in digestive organs, since pranoprofen is administered away from gastrointestinal tracts where major side effects take place. In particular, for diseases involving local pains, such as arthritis deformans, muscle ache, distention after external injuries, aches, and the like, local administrations such as the cutaneous application are more advantageous for avoiding side effects and for maintaining a higher pranoprofen concentration at injured areas than the case where pranoprofen is dosed via circulating blood. Because of this, an ointment composition comprising pranoprofen and an organic solvent such as alcohol has been proposed in Japanese Patent Publication (ko-kai) No. 7115/1984. Pranoprofen can be well absorbed by the application of an ointment. The ointment, however, requires frequent applications, e.g., several times a day, in order to maintain its effects for a long period of time. In addition, the use of organic solvent is undesirable from the aspect of safety to the skin.